Of all the sister projects, we highlight the Wikimedia Commons first (Figure 16.1, “The English-language main page for Commons”) because the Commons is considered an integral part of Wikipedia operations these days, as well as a worthwhile and popular site in its own right, ranking among the top 300 websites worldwide. The Commons is a repository of free media, including images (both photographs and illustrations), sound files, animations, and video clips. If you produce images for the encyclopedia, you are strongly encouraged to create an account for uploading your images directly to Commons. Like other Wikimedia content, all Commons media are both free and freely licensed, but the free license guidelines are stricter on Commons than on the English-language Wikipedia, as fair-use materials are excluded completely.
You can link directly to images and other content on Commons from any language version of any Wikimedia project, without having to upload that media separately to each project. For instance, you can easily insert a picture in a Wikipedia article that is actually hosted on Commons (rather than on the English-language Wikipedia itself). By comparison, when you upload an image to the English-language Wikipedia, you can only link to it from within the English-language Wikipedia. Wikimedia Commons was founded in 2004 in order to remove some obvious redundancy among the other Wikimedia projects, such as having multiple images of the same thing on different Wikipedias. Commons can be thought of as a kind of stock photography archive of free materials, designed for the other Wikimedia projects and for anyone searching for free media. The other advantages of using Commons are apparent when you want to sort and search for media. Commons is also useful for consolidating media efforts, such as projects to take pictures or make sound files.
Because all the language projects may use it, Commons is multilingual; image descriptions may be in any language, and the Commons main page interface and welcome page has been translated into a few dozen languages (links appear at the top of the main page). Commons has been so successful that nearly 3,000,000 files had been uploaded by mid-2008.
Searching Commons for images and media files is easier than searching Wikipedia. To begin searching on Commons, use the left sidebar search box or the search box in the upper-right corner of the main page (Figure 16.1, “The English-language main page for Commons”). This searches through filenames, file descriptions, gallery pages, and category names. As with Wikipedia's search, you can choose to search specific namespaces by checking the boxes for those namespaces at the bottom of your search results.
The main namespace on Commons, equivalent to the Article namespace on Wikipedia, is often called the Gallery namespace; use this namespace for producing galleries, or collections of images. The Gallery namespace does not have a special prefix. Galleries provide a way to group related images together, making them similar to Wikipedia's lists. If a gallery page with a name matching your search terms exists, this page will be displayed first in the search results.
From your search page results, you will also see a link to the external Mayflower search engine, a special tool developed for image searching. If you use Mayflower, your search results will be displayed as a thumbnail gallery of images, which can be helpful if you are searching for just the right picture for a Wikipedia article.
You can browse Commons in a number of ways. If you start at the Commons main page and scroll down, you'll see a wide variety of categories to browse by, including topic, location, content type, and categories of files arranged by license or source. One good way to start browsing is in the Featured images and Quality images categories, which are Common's equivalent of featured and good articles.
To link to a file on Commons from Wikipedia, use the same image syntax as described in Chapter 9, Images, Templates, and Special Characters. The image will appear just like an image you uploaded directly to Wikipedia. For instance, in a Wikipedia article, if you want to display an image with this URL:
http://commons.wikimedia.org/wiki/Image:file123.jpg
you can simply use this syntax in the Wikipedia article:
[[Image:file123.jpg|thumb|descriptive text]]Use the filename from Commons with the image prefix, but nothing else. When a reader clicks the image to view its description, the text from Commons will be displayed.
Anyone can participate in Commons by uploading media or by helping to organize and describe existing images. You have to create an account or log in with a global Wikimedia account (see "Project Accounts and Single-User Login" on Section 1, “Wikimedia Commons”) to upload a file. If you create a new account, the procedure is similar to creating an account on Wikipedia (described in Chapter 11, Becoming a Wikipedian).
All images and other media uploaded to Commons must fall within the inclusion guidelines of one of the other Wikimedia projects. Media files that are not potentially useful for any Wikimedia project are, therefore, beyond the scope of Commons. Note that the site isn't a personal image hosting service; your birthday party snaps don't belong here!
Additionally, all content on Commons must be completely freely licensed; fair-use images, such as you'll sometimes find on the English-language Wikipedia, are not acceptable. All content must be reusable by anyone for any purpose, including commercial uses. The licenses that Commons will accept include the following:
Public domain images, which are released without any restriction. Certain works produced by the US government and others are automatically placed in the public domain, but any individual may also release work into the public domain.
The Creative Commons free licenses, CC-BY and CC-BY-SA, both of which require attribution of the original author but allow commercial reuse. The Creative Commons licenses are also "copyleft" licenses, with similar features to the GFDL; find out more at [[Commons:Choosing a license]] and http://creativecommons.org/. The Creative Commons licenses CC-NC and CC-ND are not accepted by Commons; if you're not prepared to allow commercial reuse, then Commons is not for you.
The GFDL, which probably discourages commercial reuse because the entire GFDL license must be reprinted with the image.
Commons will not accept a number of image types, including screenshots of copyrighted software, scans of copyrighted works (such as book or album covers), or screen captures of television programs. Of course, any other copyrighted work that is not your own is also unacceptable. [[Commons:Licensing]] gives the full story, including legal information for a number of other non-US jurisdictions.
Commons accepts a variety of file types. Preferred file types include JPEG for photography, SVG for illustrations, and Ogg for audio and video; [[Commons:File types]] gives more information. For audio and video, MP3, WAV, and so on, are not free formats and are therefore not acceptable.
Uploading an image or media file to Commons is similar to uploading files on Wikipedia (see Chapter 9, Images, Templates, and Special Characters). You can access the upload form via a link on the left-hand sidebar. A series of several steps will guide you through the process, or you can jump directly to the upload form from the first page.
Choose the image's origins; if you created the image, simply say so.
Choose the appropriate license, as discussed in the previous section.
Choose an appropriate descriptive filename. Do not simply use the filename from your digital camera; choose a helpful name. Images and files cannot be renamed after they've been uploaded, though you can upload new versions of the image. If you happen to choose the same name as an existing file, a warning appears, and you'll be asked to double-check that you really want to upload a new version.
Add an appropriate description. If you created the image, what is it a picture of? Where and when was it taken? What is your name or username? Remember that this text will help other users find your image.
For bulk uploading, see [[Commons:Tools]], which lists a number of tools for uploading multiple files quickly, as well as other helpful tools such as experimental search engines.
If you'd like to contribute media but don't know how to get started, try [[Commons:Picture requests]]. If you are looking for that perfect picture for a Wikipedia article, you can also make a request here. Requests are often for images of particular places, so you can look to see if any requests are for images of places near you before going to shoot photos.
Once you've uploaded an image, you need to categorize it. Good categorization makes finding images easy on Commons. Anyone can help out with this sorting process; you don't have to have an account. [[Commons:First steps/Sorting]] has more information on the sorting and categorizing process.
If you have a new image, have described it specifically, and uploaded it, the next step is to place it in an appropriate category. In general, place images in the most narrow category possible. For instance, an image of a paperclip belongs under [[Category:Paperclips]], which is better than [[Category:Fasteners]] or [[Category:Office equipment]]. Categorize all images by topic and by other meta-level categories, for instance, by the license that applies to them.
[[Category:Topics]] is the topmost category for topics on Commons; as on Wikipedia, you can drill down into subcategories from here (this process is described fully in Chapters Chapter 3, Finding Wikipedia's Content and Chapter 8, Make and Mend Wikipedia's Web). An alternative way to find the appropriate category is to check images similar to your own and see how they're categorized. For instance, try searching for your image's topic to see if Commons already has a gallery page; then study how the images on this page are categorized.
You can add images both to a category and to the appropriate gallery page (Figure 16.2, “A photo gallery”). To add your image to a gallery page, simply go to the gallery page and edit it. You'll see images placed in between <gallery> tags, like this:
<gallery> Image:Mars Valles Marineris.jpeg|Valles Marineris on Mars Image:Mars Hubble.jpg|Mars seen by the Hubble Space Telescope, Realistic Colors </gallery>
You can add your image between those two gallery-tags (one opening and one closing tag) in the following way:
Image:Your photo name.jpg|A brief description
After saving your edit to the gallery page, you'll see your image as a thumbnail in the gallery. Unlike incorporating a single image in a Wikipedia article, you don't use the [[ and ]] brackets around the image. You can also categorize sound and video files and add them to a gallery page the same way, except that media files display a sound file icon in the gallery instead of an image.
Along with categorizing images, other projects you can get involved with include identifying and describing unknown images (at [[Category:Unidentified subject]]) and, for those with graphics experience, cleaning up images in the Graphics Lab (at [[Commons:Graphic Lab]]). Commons also has two projects that anyone can get involved with to review and pick out the highest-quality images: featured pictures, which chooses outstanding work (much like featured articles on Wikipedia); and quality images, which reviews and identifies images that meet certain technical criteria that are useful for Wikimedia projects. Anyone can nominate his or her own work for quality images at [[Commons:Quality images candidates]].
